1. Field of the Invention
The present invention relates to a shampoo composition which does not cause skin irritation and roughness. The composition comprises a monoalkyl ester salt of phosphoric acid as an active detergent component and a trialkylaminoacetobetaine or trialkylaminopropane-sulfobetaine blended with the active detergent component at a specific ratio.
2. DESCRIPTION OF THE PRIOR ART
As surface active agents for shampoos, there have heretofore been widely used anionic surface active agents such as alkyl ester salts of sulfuric acid, polyoxyethylene alkyl ester salts of sulfuric acid, alkylbenzenesulfonic acid salts and .alpha.-olefinsulfonic acid salts. However, it has been confirmed that these surface active agents cause skin irritation to a greater or lesser degree, and when shampoos containing these surface active agents are used repeatedly, roughening of the skin readily occurs. It is known that non-ionic surface active agents cause little or no skin irritation, but they are inferior to anionic surface active agents in foaming power and detergency. Therefore, incorporation of non-ionic surface active agents into detergents, such as shampoos, is not preferred. Surface active agents of the phosphoric acid ester type are known as anionic surface active agents in the art, but since each of the conventional surface active agents of the phosphoric acid ester type is a mixture of a monoester and a diester or a mixture of a monoester, a diester and a triester, if they are used in their normal state, their water solubility is extremely low and they do not manifest a substantial foaming power. Therefore, the use of these surface active agents in detergent compositions involves various difficulties.